Method of and apparatus for winding web

ABSTRACT

When an elongate film is initially wound around a core, it is wound under a low winding tension command value T 1  corresponding to the length of the core. Then, after the tension is progressively increased at a predetermined rate, the elongate film is wound while its tension is gradually lowered from a high winding tension command value T 3.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional of U.S. application Ser. No. 10/014,516, filed Dec.14, 2001, which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of and an apparatus forwinding a web around a core.

2. Description of the Related Art

It has been known in the art to wind a web such as an elongate film orsheet of paper around a core to produce a high-quality roll which isfree of wrinkles and edge undulations or irregularities by winding theweb in intimate contact with a contact pressure roller to prevent airfrom being entrapped in the web as it is wound, thus producing the rollin a well wound state (see Japanese laid-open patent publication No.11-59985).

According to the known process, since the contact pressure roller isheld in direct contact with the web, it tends to degrade the quality ofthe web particularly if the web is a delicate material such as a film.

There has been proposed in the art a process of winding a web in amanner to prevent the quality of the web from being lowered and also toprevent the web from developing wrinkles. According to the proposedprocess, the web is wound under a low tension which is 70% or less ofthe basic winding tension in an initial web winding stage, and, when thenumber of turns of the web becomes 1/10 of the number of turns which isto be finally achieved, the winding tension is sharply returned to thehigh tension, after which the web is wound under a progressivelydecreasing tension (see Japanese laid-open patent publication No.60-112562).

The above proposed process is disadvantageous in that since the windingtension is sharply changed from the low tension to the high tension, theweb is subjected to an excessive load and liable to be deterioratedunder the excessive load applied thereto. Furthermore, as shown in FIG.22 of the accompanying drawings, because possible deformation of a corea around which a web f is wound is not taken into account, an end face bof the wound web f may possibly develop edge undulations orirregularities depending on the tension which is applied to the web dwhile it is being wound. Specifically, if the web a is curved while theweb f is being wound, the web f is shifted axially of the core a,producing edge undulations or irregularities on the end face b. Suchedge undulations or irregularities cause variations in the width L ofthe produced roll. Therefore, when the roll is supplied to a subsequentprocess of packaging the roll in a light-shielded state, the roll maynot be packaged well in the light-shielded state for desired performanceand may possibly suffer fogging due to exposure to light. In addition,the roll may not well fit an image forming apparatus such as an imagesetter or the like, e.g., may not be inserted into a magazine which isto be loaded into the image forming apparatus.

A film rewinding machine for automatically winding an elongate film on acore and a cutting machine for cutting a wide raw film into an elongatefilm of given width and then automatically winding the elongate film ona core employ a winding mechanism for supporting the elongate film onthe outer circumferential surface of the core when the core is rotatedin a winding position.

As disclosed in Japanese patent publication No. 57-40052 (hereinafterreferred to as “prior art 1”), the winding mechanism has a holder forholding a spool, angularly movably mounted on the distal end of a beltwrapper, and an actuating mechanism for reciprocally moving the beltwrapper until the central axis of the spool held by the holder isaligned with the central axis of a winding barrel.

A strip coiler disclosed in Japanese utility model publication No.48-38149 (hereinafter referred to as “prior art 2”) comprises a mandrelfor winding a strip as a coil, a plurality of wrapper rolls and wrapperroll plates disposed around the mandrel, and a fluid pressure cylinderfor pressing the wrapper rolls into and retracting the wrapper rollsfrom a position to start winding the strip.

According to the prior art 1, the belt wrapper has an opening alignedwith the direction in which the film enters, i.e., the direction inwhich the film tension acts. Therefore, when the elongate film is woundaround the core (spool), the core may possibly be greatly flexed underthe film tension. If the core is flexed, then the film tensionconcentrates on the opposite edges of the core, causing the elongatefilm to run unstably and disturbing the wound configuration of theelongate film.

According to the prior art 2, the strip coiler is designed for thepurpose of setting a gap between the mandrel (corresponding to the core)and each wrapper roll depending on the thickness of the strip(corresponding to the elongate film) to be wound in order to keep thestrip as it starts to be wound in a good coil configuration. The stripcoiler has nothing incorporated therein for preventing the mandrel frombeing flexed under the strip tension. Stated otherwise, no considerationis given to achieving a balance between the strip tension and the forceto press the wrapper rolls, and hence the strip tension tends to act onthe mandrel to cause the mandrel to be flexed.

According to the prior art 2, furthermore, gaps are provided between themandrel and the wrapper rolls and wrapper roll plates, and the strip iswound on the mandrel through the gaps. However, when the elongate filmis wound around the core in this manner, the elongate film hasdifficulty in being held in intimate contact with the outercircumferential surface of the core, and the wound configuration becomesunstable on the end faces of the wound film roll.

SUMMARY OF THE INVENTION

It is a general object of the present invention to provide a method ofand an apparatus for winding a web around a core in a highly neatlywound state without causing damage to the web and forming edgeundulations or irregularities on end faces of a roll that is produced ofthe wound web.

A major object of the present invention is to provide a method ofwinding a web smoothly and highly accurately around a core in a simpleprocess.

Another object of the present invention is to provide an apparatus forwinding a web while reliably preventing the core from being flexed witha simple arrangement.

With a method of and an apparatus for winding a web around a coreaccording to the present invention, the web is wound to a given lengtharound the core under a low tension thereby imparting prescribedrigidity to the core without deforming the core. The length to which theweb is wound under the low tension is set so as to correspond to thelength of the core, thus preventing a quality failure such as a stepwiseweb shift on a shorter core.

Then, after the tension of the web is progressively increased at apredetermined rate, the tension is reduced at a predetermined rate whilethe web is being wound around the core. The web is thus wound around thecore to which sufficient rigidity is imparted, without being subjectedto an excessive load. As a result, a roll produced by winding the webaround the core is free of edge undulations or irregularities on its endfaces, and is of a good quality free of damage and windingirregularities.

In a method of winding a web around a core according to the presentinvention, a web is supported on the outer circumferential surface of acore by a plurality of rollers, and the core is rotated with a gap beingdefined by blocks for the passage of the web between the blocks and theouter circumferential surface of the core. The rollers and the blocksare retracted from the core successively from regions where a leadingend of the web has passed. After the web is wound around the core by atleast one turn, all the rollers and the blocks are retracted from thecore.

Since the rollers and the blocks are retracted from the coresuccessively from regions where the leading end of the web has passed,only the leading end of the web is held when the web is initially woundaround the core. Therefore, the web is not loosened on the outercircumferential surface of the core under the tension of the web. As aconsequence, a high-quality wound product with a desired woundconfiguration maintained reliably can efficiently be obtained through asimple process.

In an apparatus for winding a web around a core according to the presentinvention, a winding mechanism for guiding the web around the core whenthe core is rotated has a movable pressing roller for pressing the webagainst the core to support the web thereon and for being pressedagainst the core in a direction opposite to the direction in which thetension of at least the web is applied, and a plurality of movableblocks for creating a gap for passage of the web between the movableblocks and an outer circumferential surface of the core.

The movable pressing roller presses the core in the direction oppositeto the direction in which the tension of the web is applied, to keep thetension of the web and the pressing forces applied by the pressingroller in equilibrium. Consequently, when the web is wound around thecore, the core is effectively prevented from being flexed under thetension of the web, making it possible to reliably obtain a stable woundconfiguration with a simple arrangement.

The above and other objects, features, and advantages of the presentinvention will become more apparent from the following description whentaken in conjunction with the accompanying drawings in which preferredembodiments of the present invention are shown by way of illustrativeexample.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic elevational view of a film processing and cuttingmachine to which a method of and an apparatus for winding a web around acore according to a first embodiment of the present invention areapplied;

FIG. 2 is a block diagram of a control circuit of a film windingapparatus of the film processing and cutting machine shown in FIG. 1;

FIG. 3 is a diagram showing the relationship between speed commandvalues for feeding a film and winding tension command values in thecontrol circuit of the film winding apparatus of the film processing andcutting machine shown in FIG. 1;

FIG. 4 is an elevational view of a film winding apparatus according to asecond embodiment of the present invention;

FIG. 5 is a perspective view of a core rotating mechanism of the filmwinding apparatus;

FIG. 6 is a plan view of the core rotating mechanism;

FIG. 7 is a perspective view of a block wrapper and a first unit body ofa film winding mechanism;

FIG. 8 is a side elevational view showing a structure of the blockwrapper;

FIG. 9 is a perspective view of a winding nip roller unit of the filmwinding apparatus;

FIG. 10 is a perspective view of a cutting mechanism of the film windingapparatus;

FIG. 11 is a view illustrative of the manner in which an elongate filmstarts being wound around a core;

FIG. 12 is a view illustrative of the manner in which the winding niproller unit is released from the core;

FIG. 13 is a view illustrative of the manner in which a side wrapper isreleased from the core;

FIG. 14 is a view illustrative of the manner in which an upper wrapperis released from the core;

FIG. 15 is a view illustrative of the manner in which the elongate filmis wound around the core;

FIG. 16 is a view illustrative of the manner in which a film roll madeof the elongate film wound around the core is discharged;

FIG. 17 is a view illustrative of the manner in which the elongate filmis cut from the film roll;

FIG. 18 is a view illustrative of the manner in which the end of the cutelongate film is wound, producing the film roll;

FIG. 19 is a perspective view showing the manner in which the elongatefilm is wound around the core without using the block wrapper;

FIG. 20 is a perspective view showing the manner in which the elongatefilm is wound around the core using the block wrapper;

FIG. 21 is a view of another winding nip roller unit; and

FIG. 22 is a perspective view illustrative of the manner in which a rollis produced by winding a web around a core.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows in schematic elevation a film processing and cuttingmachine 12 which incorporates film (web) winding apparatus 10 accordingto a first embodiment of the present invention.

The film processing and cutting machine 12 has a film delivery apparatus18 for rotating film rolls 14, each in the form of a photosensitive roll(hereinafter referred to as “film roll”) of a PET (polyethyleneterephthalate) film, a TAC (triacetylcellulose) film, a PEN(polyethylene naphthalate) film, or a photographic printing sheet usedas a base, while being kept under suitable back tension to deliver anelongate raw film (raw web) 16; a feed apparatus 20 for feeding theelongate raw film 16 successively to next processes; a cutting apparatus26 for cutting the elongate raw film 16 fed by the feed apparatus 20 attransversely spaced intervals into a plurality of elongate film blanksand cutting off film edges from the elongate film blanks, thus producinga plurality of elongate films (elongate webs) 24 a through 24 d (in thefirst embodiment, four elongate films 24 a through 24 d) having givenwidths; film winding apparatus 10 for winding the elongate films 24 athrough 24 d around respective cores 28 a through 28 d and cutting theelongate films 24 a through 24 d to given lengths, thereby producingrolls 30 a through 30 d as products; and an edge processing apparatus 34for processing unwanted edges (film edges) 32 discharged from theelongate raw film 16.

The film delivery apparatus 18 has a turret shaft 36 by which a pair offilm rolls 14 is supported for indexed movement. The film rolls 14 areselectively unwound by an unwinding motor (not shown). The feedapparatus 20 has a suction drum (reference roller) 38 serving as a mainfeed roller and a plurality of rollers 40. The suction drum 38 iscontrolled in speed to rotate according to a predetermined pattern ofperipheral speeds by a servomotor (described later on). An encoder 41 isconnected to the shaft (not shown) of the suction drum 38.

One of the rollers 40 which are disposed between the film roll 14 inoperation and the suction drum 38 is associated with a tension detector(tension pickup) 42. The tension of the film between the film roll 14and the suction drum 38 is controlled by the tension detector 42 and theunwinding motor mounted on the shaft of the film roll 14. Near theturret shaft 36, there are disposed an EPC (edge position control)sensor 44 for detecting the position of an end of the elongate raw film16 to adjust the position of the end and a splicing suction table 46 forsplicing the trailing end of the elongate raw film 16 to the leading endof a new elongate raw film 16 from the other film roll 14.

The cutting apparatus 26 has a plurality of rotary cutters 48 a, 48 bselectively positioned in cutting positions corresponding to film widthsto be achieved, for cutting the elongate raw film 16 at transverselyspaced intervals. The cutting apparatus 26 includes, in its lowerportion, separation rollers 50 a, 50 b for separating severed elongatefilms 24 a through 24 d away from each other. The film winding apparatus10 are disposed downstream of the separation rollers 50 a, 50 b with niproller pairs 52 a, 52 b interposed therebetween.

In FIG. 1, there are two left and right film winding apparatus 10associated with the elongate films 24 a through 24 d. The film windingapparatus 10 have a core rotating mechanism 58 for holding and rotatingcores 28 a through 28 d, a plurality of block wrappers (windingmechanisms) 60 for winding the elongate films 24 a through 24 d to agiven length around the cores 28 a through 28 d to produce rolls 30 athrough 30 d, a product receiving mechanism 64 for gripping thecircumferential surfaces of the elongate films 24 a through 24 d woundaround the cores 28 a through 28 d while applying a certain tension tothe elongate films 24 a through 24 d, the product receiving mechanism 64being relatively movable away from the block wrappers 60, a cuttingmechanism 66 for transversely cutting the elongate films 24 a through 24d while they are being tensioned by the product receiving mechanism 64,and a core supply mechanism 68 for automatically supplying the cores 28a through 28 d to the block wrappers 60.

Operation of the film processing and cutting machine 12 thus constructedwill briefly be described below.

A film roll 14 mounted on the film delivery apparatus 18 is unwound bythe non-illustrated unwinding motor to supply an elongate raw film 16 tothe suction drum 38 of the feed apparatus 20. The speed of the suctiondrum 38 is controlled according to a given speed pattern by theservomotor, described later on, and the length of the elongate raw film16 as it is fed (the length of the elongate raw film 16 as it is wound)is detected by the encoder 41.

The elongate raw film 16 which is adjusted in speed by the suction drum38 is fed to the cutting apparatus 26. The rotary cutters 48 a, 48 b arerotated to cut the edges 32 off the elongate raw film 16 and producefour elongate films 24 a through 24 d, which are fed to the film windingapparatus 10.

In the film winding apparatus 10, while the outer circumferentialsurfaces of cores 28 a through 28 d are being held by the block wrappers60, the suction drum 38 is rotated and the cores 28 a through 28 d arerotated by the core rotating mechanism 58. The elongate films 24 athrough 24 d are now wound respectively around the cores 28 a through 28d. After the block wrappers 60 are spaced away from the respective cores28 a through 28 d, the elongate films 24 a through 24 d are wound to agiven length around the cores 28 a through 28 d, producing rolls 30 athrough 30 d.

The product receiving mechanism 64 is elevated to hold the rolls 30 athrough 30 d, which are lowered as they are unwinding the elongate films24 a through 24 d. The cutting mechanism 66 is actuated to cut(cross-cut) the elongate films 24 a through 24 d in their transversedirection. Now, products comprising the rolls 30 a through 30 d areobtained, and supplied to a next process. The block wrappers 60 areautomatically supplied with new 28 a through 28 d, and restart a nextwinding process.

Unless the tension applied to the elongate films 24 a through 24 d isadjusted to an appropriate level when they are wound as described above,the elongate films 24 a through 24 d tend to be damaged due to excessivetension or the obtained rolls 30 a through 30 d are liable to beloosened or suffer edge undulations or irregularities. According to thefirst embodiment, these drawbacks are avoided by arranging andcontrolling the film winding apparatus 10 as follows:

FIG. 2 shows in block form a control circuit 1000 of the film windingapparatus 10. The control circuit 1000 has a speed controller 1002 forcontrolling the rotational speed of the suction drum 38, and speed andtorque controllers (core rotation control means) 1004 a through 1004 dfor controlling the rotational speeds and torques of the cores 28 athrough 28 d in the core rotating mechanism 58.

A process control computer 1008 to which a management computer 1010 isconnected is connected to the control circuit 1000 through an input unit1006. The process control computer 1008 performs process control in thefilm winding apparatus 10. The film processing and cutting machine 12has process control computers 1008 associated with respective processes.The management computer 1010 serves to manage all the process controlcomputers 1008 of the film processing and cutting machine 12.

A motor driver 1014 is connected to the speed controller 1002 through anoutput unit 1012. The motor driver 1014 is also connected to aservomotor 1016 for rotating the suction drum 38. To the speedcontroller 1002, there is connected a speed command value memory 1018for storing a speed command value supplied from the process controlcomputer 1008. The servomotor 1016 is controlled according to the speedcommand value stored in the speed command value memory 1018.

Motor drivers 1026 a through 1026 d are connected to the respectivespeed and torque controllers 1004 a through 1004 d through respectiveoutput units 1024 a through 1024 d. The motor drivers 1026 a through1026 d are connected to respective servomotors 1028 a through 1028 d forwinding elongate films 24 a through 24 d around cores 28 a through 28 d.To the speed and torque controllers 1004 a through 1004 d, there areconnected respective speed command value memories 1030 a through 1030 dfor storing speed command values supplied from the process controlcomputers 1008, and respective winding tension command value memories(winding tension storing means) 1032 a through 1032 d for storingwinding tension command values supplied from the process controlcomputers 1008, through respective torque converting units (torqueconverting means) 1034 a through 1034 d. The servomotors 1028 a through1028 d are controlled according to speed command values supplied fromthe speed and torque controllers 1004 a through 1004 d and windingtension command values converted by the torque converting units 1034 athrough 1034 d.

A process of controlling the film winding apparatus 10, which is carriedout by the control circuit 1000, will be described below.

Prior to a process of winding the elongate films 24 a through 24 d withthe film winding apparatus 10, the process control computer 1008 storespreset speed command values and preset winding tension command values inthe speed command value memory 1018, the speed command value memories1030 a through 1030 d, and the winding tension command value memories1032 a through 1032 d.

FIG. 3 shows in an upper portion thereof the relationship between speedcommand values for the servomotor 1016 which are stored in the speedcommand value memory 1018 and time, and FIG. 3 shows in a lower portionthereof the relationship between winding tension command values for theelongate films 24 a through 24 d which are stored in the winding tensioncommand value memories 1032 a through 1032 d and time. The speed commandvalue memories 1030 a through 1030 d store a constant speed commandvalue for the servomotors 1028 a through 1028 d.

The speed and torque controllers 1004 a through 1004 d read a constantspeed command value from the speed command value memories 1030 a through1030 d, supply a drive signal based on the speed command value from theoutput units 1024 a through 1024 d via the motor drivers 1026 a through1026 d to the servomotors 1028 a through 1028 d to rotate the cores 28 athrough 28 d.

The torque converting units 1034 a through 1034 d read a constantwinding tension command value Ti shown in FIG. 3 from the windingtension command value memories 1032 a through 1032 d, convert thewinding tension command value T1 into a torque command value, and supplythe torque command value to the speed and torque controllers 1004 athrough 1004 d. The speed and torque controllers 1004 a through 1004 dcontrol the motor drivers 1026 a through 1026 d to rotate theservomotors 1028 a through 1028 d with the torque command supplied fromthe torque converting units 1034 a through 1034 d.

After the core rotating mechanism 58 has been adjusted to the abovestate, the speed controller 1002 reads a speed command value from thespeed command value memory 1018 at a time t1, and supplies a drivesignal based on the speed command value from the output unit 1012 viathe motor driver 1014 to the servomotor 1016 thereby rotating thesuction drum 38. The suction drum 38 is accelerated from the time t1 toa time t2, and then rotated at a constant speed v1 to deliver theelongate raw film 16 to the film winding apparatus 10.

The elongate raw film 16 delivered by the suction drum 38 is cut by thecutting apparatus 26 into four elongate films 24 a through 24 d, whichare then supplied to the core rotating mechanism 58 of the film windingapparatus 10. Then, the elongate films 24 a through 24 d start beingwound around the cores 28 a through 28 d that are rotated by theservomotors 1028 a through 1028 d. Since the servomotors 1028 a through1028 d are controlled to produce a torque value which is equal to aconstant torque command value that is obtained by converting theconstant winding tension command value T1, a constant tension T1 isapplied to the elongate films 24 a through 24 d when they are woundaround the cores 28 a through 28 d.

Then, the speed controller 1002 reads a speed command value from thespeed command value memory 1018, and accelerates the suction drum 38from a speed v1 to a speed v2 in an interval from a time t3 to a timet6, delivering the elongate raw film 16 to the film winding apparatus10.

The torque converting units 1034 a through 1034 d convert a windingtension command value, which gradually increases from the windingtension command value T1 read from the winding tension command valuememories 1032 a through 1032 d to a winding tension command value T3 setdepending on the length of the cores 28 a through 28 d during aninterval from a time t4 to a time t5 which is set depending on thelength of the cores 28 a through 28 d, into a torque command value. Thespeed and torque controllers 1004 a through 1004 d then supply thetorque command value to the motor drivers 1026 a through 1026 d tocontrol the servomotors 1028 a through 1028 d. As a result, the elongatefilms 24 a through 24 d are wound around the respective cores 28 athrough 28 d under winding tensions T1 through T3 which graduallyincrease.

When a time t5 is reached, the speed and torque controllers 1004 athrough 1004 d gradually reduce the torque command value from the valuecorresponding to the winding tension command value T3, and winds theelongate films 24 a through 24 d.

During this time, the acceleration to deliver the elongate raw film 16with the servomotor 1016 based on the command from the speed controller1002 is gradually reduced. At a time t6, the speed command value fromthe speed controller 1002 is set to a constant speed command value v2.The speed command value v2 is kept until a time t7, and thereafterreduced to the speed command value v1 at a time t8 and then to 0 at atime t9.

During an interval from the time t5 to the time 59, the speed and torquecontrollers 1004 a through 1004 d gradually reduce the torque commandvalue from the value corresponding to the winding tension command valueT3 to the value corresponding to the winding tension command value T2,and thereafter set the torque command value to the value correspondingto the winding tension command value T1.

The elongate films 24 a through 24 d are thus wound around therespective cores 28 a through 28 d while the tension applied to theelongate films 24 a through 24 d is being adjusted in the mannerdescribed above, thereby producing neatly wound rolls 30 a through 30 d.

Specifically, when the elongate films 24 a through 24 d start beingwound around the respective cores 28 a through 28 d, the winding tensioncommand value T1 applied to the elongate films 24 a through 24 d is keptlow. Since no large external forces are imposed on the cores 28 athrough 28 d which are not given sufficient rigidity by the elongatefilms 24 a through 24 d, the cores 28 a through 28 d are not flexed, andhence the elongate films 24 a through 24 d are neatly wound around therespective cores 28 a through 28 d.

When the elongate films 24 a through 24 d are wound to a certain lengtharound the respective cores 28 a through 28 d, they impart rigidity tothe cores 28 a through 28 d, making the cores 28 a through 28 dresistant to flexing. The tension of the elongate films 24 a through 24d is then switched to the higher winding tension command value T3,allowing the elongate films 24 a through 24 d to be wound at a highspeed around the cores 28 a through 28 d without being made unstable bybecoming loose. For longer cores 28 a through 28 d, the length of theelongate films 24 a through 24 d wound under the lower winding tensioncommand value T1 is set to a larger value, so that the elongate films 24a through 24 d can be wound around the cores 28 a through 28 d withoutflexing the cores 28 a through 28 d.

For shorter cores 28 a through 28 d, since the shorter cores 28 athrough 28 d are sufficiently rigid, the length of the elongate films 24a through 24 d wound under the lower winding tension command value T1 isset to a smaller value, and the higher winding tension command value T3switched from the lower winding tension command value T1 is set to alarger value. Thus, the elongate films 24 a through 24 d are preventedfrom being displaced while they are being wound, and can be neatly woundaround the cores 28 a through 28 d.

In the first embodiment, when the winding tension command value isincreased from the value T1 to the value T3, it is increased graduallyat a certain rate without abrupt tension variations. Consequently, theelongate films 24 a through 24 d are wound around the respective cores28 a through 28 d without being damaged.

After the tension of the elongate films 24 a through 24 d has reachedthe winding tension command value T3, the elongate films 24 a through 24d are wound while their tension is being gradually reduced. In thismanner, the elongate films 24 a through 24 d are wound without beingdisplaced and the ends of the rolls 30 a through 30 d are not disturbedor undulated, so that the rolls 30 a through 30 d are in a held in avery neatly wound state.

The winding tension values stored in the winding tension command valuememories 1032 a through 1032 d may be set to individual values for therespective rolls 30 a through 30 d and may be independently controlled.

Examples under specific conditions will be described below.

1ST EXAMPLE

For winding elongate films 24 a through 24 d having a width of 1220 mmaround respective cores 28 a through 28 d having a length of 1220 mm andan outside diameter of 3 inches, the elongate films 24 a through 24 dwere wound to a length of 8 m (about 30 turns) under a tension T1=7.84N/100 mm, and then wound to 10 m while increasing the tension from T1 toa tension T3=17.64 N/mm. Then, while gradually reducing the tension T3at a rate of 20%, the elongate films 24 a through 24 d were wound to 61m, producing rolls 30 a through 30 d. The number of turns wound underthe low tension T1 was about 15% of the entire number of turns.

In 1st Example, though the cores 28 a through 28 d were elongate andliable to be flexed, any disturbance or undulation on the ends of therolls 30 a through 30 d was less than a target value of 0.5 mm. Theelongate films 24 a through 24 d were not displaced on the cores 28 athrough 28 d, and sufficiently neatly wound around the respective cores28 a through 28 d.

2ND EXAMPLE

For winding elongate films 24 a through 24 d having a width of 150 mmaround respective cores 28 having a length of 150 mm and an outsidediameter of 3 inches, the elongate films 24 a through 24 d were wound toabout one-half of a turn around the cores 28 a through 28 d under atension T1=7.84 N/100 mm, and then wound while increasing the tensionfrom T1 to a tension T3=24.5 N/mm. Then, while gradually reducing thetension T3 at a rate of 20%, the elongate films 24 a through 24 d werewound to 61 m, producing rolls 30 a through 30 d. The number of turnswound under the low tension T1 was about 0.5% of the entire number ofturns.

In 2nd Example, because the cores 28 a through 28 d were short and lessliable to be flexed, the elongate films 24 a through 24 d could be woundunder a high tension from the start of the winding process, producingneat rolls 30 a through 30 d whose elongate films 24 a through 24 d werenot disturbed or undulated and displaced.

Other Examples are shown in Table 1 below. In these Examples, the cores28 a through 28 d had an inside diameter of 73.7 mm, an outside diameterof 77.9 mm, and a length of which was 0.5 to 1.0 mm smaller than thewidth of the elongate films 24 a through 24 d. By setting the length ofthe elongate films 24 a through 24 d to be wound around cores 28 athrough 28 d under the low tension T1 as shown in Table 1 with respectto the overall length of rolls 30 a through 30 d, any disturbance orundulation of the ends of the rolls could be held to an allowable rangeof 0.5 mm. TABLE 1 Winding ratio under low Axial film length tension T1310 mm 0.5% 381 mm 0.5% 761 mm 0.5% 838 mm 0.5% 1220 mm 1.5%

FIG. 4 shows a film (web) winding apparatus 10 a according to a secondembodiment of the present invention. In a similar manner to the filmwinding apparatus 10 according to the first embodiment, the film windingapparatus 10 a is incorporated in the film processing and cuttingmachine 12. Those parts of the film winding apparatus 10 a which areidentical to those of the film winding apparatus 10 are denoted byidentical reference characters, and will not be described in detailbelow.

As shown in FIG. 4, a nip roller pair 52 a comprises a backup roller 54connected to a rotary actuator (not shown) and a nip roller 56 movabletoward and away from the backup roller 54. The backup roller 54 has itsperipheral speed set such that its feed speed in the direction indicatedby the arrow B is higher than the suction drum 38. When the nip roller56 is pressed against the backup roller 54 in sandwiching relation tothe elongate films 24 a, 24 b, a certain tension is applied to elongatefilms 24 a, 24 b as they are fed into the cutting apparatus 26 though notension is applied to the elongate films 24 a, 24 b downstream of thenip roller 56.

As shown in FIG. 5, the core rotating mechanism 58 has two cores 28 a,28 b disposed coaxially with each other and positionally adjustable bytwo guide rails 72 a, 72 b and a ball screw 74 which extend in thedirections indicated by the arrow D (axial directions of the cores 28 a,28 b) for simultaneously winding the elongate films 24 a, 24 b aroundthe respective cores 28 a, 28 b.

As shown in FIGS. 5 and 6, the core rotating mechanism 58 has twomovable bases 76 a, 76 b supported on the guide rails 72 a, 72 b and theball screw 74. The movable bases 76 a, 76 b support thereon respectivenuts 78 a, 78 b threaded over the ball screw 74 and respectiveservomotors 82 a, 82 b for rotating the respective nuts 78 a, 78 bindividually through belt and pulley means 80 a, 80 b, respectively.

Cylinders 84 a, 84 b are fixed respectively to the movable bases 76 a,76 b and have respective rods 86 a, 86 b projecting therefrom to whichrespective take-up arms 88 a, 88 b are secured. Core chucks 90 a, 90 bare rotatably mounted on the respective take-up arms 88 a, 88 b. Thecore chuck 90 a can be rotated by a servomotor 92.

The servomotor 92 is fixedly mounted on the movable base 76 a and has adrive shaft 94 to which a rotary tube 98 is coupled by a belt and pulleymeans 96. The rotary tube 98 is supported on the movable base 76 a andhas spline grooves defined in its inner circumferential surface, and aspline shaft 100 is fitted in the spline grooves. The spline shaft 100is rotatably supported on a casing 102 fixed to the take-up arm 88 a.The core chuck 90 a is coupled to an end of the spline shaft 100 by abelt and pulley means 104.

As shown in FIG. 7, the block wrappers 60 are individually movable on aunit body 200 in the directions indicated by the arrow C which aretransverse to the axial directions of cores 28 a, 28 b (the directionsindicated by the arrow D). The unit body 200 is movable in thedirections indicated by the arrow C by a drive means 202. The drivemeans 202 has a pair of frames 204 spaced from each other by a certaindistance in the directions indicated by the arrow D. A servomotor 206 ismounted on at least one of the frames 204. The servomotor 206 has adrive shaft 208 to which a ball screw 212 is coupled through a belt andpulley means 210. The ball screws 212 are rotatably supported on uppersurfaces of the frames 204, and are threaded through respective nuts(not shown) mounted on movable bodies 214. Each of the movable bodies214 is supported on a guide rail 216 mounted on one of the frames 204.

The unit body 200 is removably fixed between the movable bodies 214.Each of the block wrappers 60 can be fixed to the unit body 200selectively in a winding position P1 and a retracted position P2.

As shown in FIG. 8, the block wrappers 60 have respective upper wrappers300 mounted on a base 254 and vertically movable by a lifting andlowering means 302, and side wrappers 304 mounted on the base 254 andhorizontally movable by a moving means 306. The lifting and loweringmeans 302 has a rectangular support tube 308 mounted on the base 254 andextending vertically upwardly, and an actuator with a pressing forceadjusting function in the form of a vertical cylinder 310, for example,is fixed to a side panel of the rectangular support tube 308. Thecylinder 310 has an upwardly extending rod 312 to which there is fixed avertically movable base 314 that is vertically movably supported on aguide rail 316 fixedly mounted another side panel of the rectangularsupport tube 308. Each of the upper wrappers 300 is mounted on the lowersurface of a distal end portion of the vertically movable base 314.

Each of the upper wrappers 300 has a block 317 fixed to the verticallymovable base 314. The block 317 has a guide surface 318 on its end closeto the cores 28 a, 28 b which has a radius of curvature slightly greaterthan the radius of curvature of the outer circumferential surface of thecores 28 a, 28 b. A gap 319 for passing the elongate films 24 a, 24 btherethrough is defined between the guide surface 318 and the cores 28a, 28 b. First and second free rollers (first and second pressingrollers) 320 a, 320 b are rotatably supported on the block 317 andpositioned on the guide surface 318 for pressing the elongate films 24a, 24 b against the outer circumferential surface of the cores 28 a, 28b. The first and second free rollers 320 a, 320 b are movable toward andaway from the cores 28 a, 28 b and can be pressed against the cores 28a, 28 b in the direction indicated by the arrow V2 which is opposite tothe direction indicated by the arrow V1 in which the elongate films 24a, 24 b are tensioned.

The first and second free rollers 320 a, 320 b are symmetricallypositioned with respect to a hypothetical reference line LV whichextends parallel to the direction indicated by the arrow V1 in which theelongate films 24 a, 24 b are tensioned and also extends through centersof the cores 28 a, 28 b. Specifically, the first and second free rollers320 a, 320 b are axially symmetrically positioned at equal distances Kfrom the hypothetical reference line LV extending across the cores 28 a,28 b.

The moving means 306 comprises an actuator with a pressing forceadjusting function in the form of a horizontal cylinder 322, forexample, mounted on the base 254. The cylinder 322 has a horizontallyextending rod 324 to which there is fixed a movable base 326 that issupported on a rail 328 on the base 254 for movement in the directionsindicated by the arrow C. Each of the side wrappers 304 is mounted onthe movable base 326.

Each of the side wrappers 304 has a block 329 having a guide surface 330on its end close to the cores 28 a, 28 b which has a radius of curvatureslightly greater than the radius of curvature of the outercircumferential surfaces of the cores 28 a, 28 b. A gap 331 for passingthe elongate films 24 a, 24 b therethrough is defined between the guidesurface 330 and the cores 28 a, 28 b. Third and fourth free rollers 332,334 are rotatably supported on the block 329 and positioned on the guidesurface 330.

The third free roller 332 as a third pressing roller is disposed on ahypothetical line LH that extends diametrically across the cores 28 a,28 b transversely to the hypothetical reference line LV. The fourth freeroller 334 as a receiving roller is disposed in engagement with thecores 28 a, 28 b in substantially opposite relation to the first andsecond free rollers 320 a, 320 b about the cores 28 a, 28 b. The fourthfree roller 334 is supported on a swing block 336 for angular movementwith respect to the side wrapper 304. An air cylinder 338 as an airspring abuts against the swing block 336 for reliably holding the fourthfree roller 334 against the cores 28 a, 28 b even if the cores 28 a, 28b have a slightly different outside diameter.

As shown in FIG. 4, a winding nip roller unit 400 serving as a windingmechanism is incorporated in a position confronting the block wrappers60. As shown in FIGS. 4 and 9, the winding nip roller unit 400 compriseswinding nip rollers (pressing rollers) 402 disposed in confrontingrelation to the third free roller 332 for pressing and supporting theelongate films 24 a, 24 b on the outer circumferential surface of thecores 28 a, 28 b, and lower winding rollers (pressing rollers) 404 forcausing ends of the cut elongate films 24 a, 24 b to extend along theouter circumferential surfaces of the cores 28 a, 28 b. For example, 14winding nip rollers 402 and 14 lower winding rollers 404 are arrayed inthe directions indicated by the arrow D in association with therespective block wrappers 60.

An upper plate 408 is fixed to a unit body 406 of the winding nip rollerunit 400, and the winding nip rollers 402 are individually rotatablymounted on the distal end of the upper plate 408. A movable lower plate410 is disposed below the upper plate 408 for movement along a linearguide 412 in the directions indicated by the arrow C. A pair ofcylinders 414 is fixed to the upper plate 408 and has rods 416 extendingtherefrom which are fixed to the lower plate 410.

A swing arm 420 is swingably supported on a distal end of the lowerplate 410 by a spring 418. The lower winding rollers 404 are rotatablymounted on a distal end of the swing arm 420. A pair of racks 422 isfixed to the lower plate 410, and the upper plate 408 has openings 424defined therein in alignment with the respective racks 422. Pinions 426are held in mesh with the respective racks 422 through the openings 424.The pinions 426 are integrally supported by a rod 428.

The unit body 406 incorporates the cutting mechanism 66. As shown inFIGS. 4 and 10, the cutting mechanism 66 comprises a rodless cylinder430 mounted on the unit body 406 by a rod 432 which extends axially ofthe cores 28 a, 28 b in the directions indicated by the arrow D. A basemember 434 is fixed to the rodless cylinder 430 and guided along alinear guide 436 in the directions indicated by the arrow D. Parallel tothe linear guide 436, there extends a rack 438 meshing with a firstpinion 440 which is held in mesh with a second pinion 442.

A disk-shaped cross cutter blade 446 is fixed to the second pinion 442.A sorting guide 448 for guiding the elongate films 24 a, 24 b isdisposed at a distal end of the cross cutter blade 446. The elongatefilms 24 a, 24 b may be cut off by the cross cutter blade 446 alone orthe cross cutter blade 446 as an upper blade and a lower blade disposedin confronting relation to the upper blade. The rodless cylinder 430 maybe replaced with a motor, a timing belt, and a pulley for moving thebase member 434.

A free roller 450 supported on the unit body 406 is disposed below thecutting mechanism 66 (see FIG. 4).

As shown in FIG. 4, the product receiving mechanism 64 has a verticallymovable frame 500 which can be stopped selectively in four positions,i.e., in an upper end position, an intermediate standby position, a filmcutting position, and a lower end position, by a servomotor 502. Theservomotor 502 has a drive shaft 504 operatively connected to a verticalball screw 506 that is threaded through a nut 508 mounted on thevertically movable frame 500.

To the vertically movable frame 500, there is fixed a cylinder 510having an upwardly extending rod 512 coupled to a block 514. A first arm516 extends upwardly from the block 514 and supports on its distal endan ejection roller 518 to which a tensioning servomotor 520 is coupledby a belt and pulley means 522. The block 514 includes a second arm 524with a free roller 526 rotatably supported on its distal end.

Between the first and second arms 516, 524, there is disposed a conveyor528 for ejecting products. To the vertically movable frame 500, there issecured a cylinder 530 having an upwardly extending rod 532 to which arider roller 538 is connected by a swing arm 536.

The core supply mechanism 68 has a pusher 550 of a comb-toothedstructure having teeth aligned with the respective gaps between theblock wrappers 60 for smoothly supplying cores 28 a, 28 b to a coretransfer position P3.

Operation of the film winding mechanism 10 a thus constructed will bedescribed below.

When the elongate films 24 a, 24 b are wound around the cores 28 a, 28 bin the film winding apparatus 10 a, as shown in FIG. 11, the cores 28 a,28 b are placed in the winding position with their circumferentialsurface gripped by the block wrapper 60, and the opposite ends of thecores 28 a, 28 b are supported by the core chucks 90 a, 90 b.

In the winding nip roller unit 400, the unit body 406 is moved to movethe winding nip roller 402 toward the cores 28 a, 28 b, thus supportingthe elongate films 24 a, 24 b on the outer circumferential surfaces ofthe cores 28 a, 28 b. As shown in FIG. 9, the cylinder 414 is actuatedto move the lower plate 410 forward in the direction indicated by thearrow Cl with respect to the upper plate 408, causing the lower windingroller 404 mounted on the lower plate 410 to wind the leading endportions of the elongate films 24 a, 24 b around the cores 28 a, 28 bthrough an angular range of about 90°.

Then, the suction drum 38 is rotated, and the drive torque of theservomotor 92 enables the belt and pulley means 104 to start rotatingthe core chuck 90 a, as shown in FIGS. 5 and 6. The cores 28 a, 28 b arenow rotated to wind the elongate films 24 a, 24 b around the cores 28 a,28 b through about 180° from the position where the elongate films 24 a,24 b have been held by the lower winding roller 404 (the elongate films24 a, 24 b are actually wound around the cores 28 a, 28 b through about270°), after which the winding nip roller 402 and the lower windingroller 404 of the winding nip roller unit 400 are spaced away from thecores 28 a, 28 b (see FIG. 12).

The servomotor 92 is energized to wind the elongate films 24 a, 24 baround the cores 28 a, 28 b further through about 90° (a total of about360°). Thereafter, as shown in FIG. 13, the side wrapper 38 of eachblock wrapper 60 is moved away from the cores 28 a, 28 b by the cylinder322. When one turn or more of the elongate films 24 a, 24 b issubsequently wound around the cores 28 a, 28 b, as shown in FIG. 14, theupper wrapper 300 of each block wrapper 60 is retracted upwardly by thecylinder 310, and the nip roller 56 is spaced away from the backuproller 54.

As described above, when the elongate films 24 a, 24 b start being woundaround the cores 28 a, 28 b, as shown in FIG. 11, the upper wrapper 300,the side wrapper 304, the winding nip roller 402, and the lower windingroller 404 of the winding mechanism are positioned around the cores 28a, 28 b. Then, the core rotating mechanism 58 is actuated to rotate thecores 28 a, 28 b in the direction indicated by the arrow E in FIG. 12 towind the elongate films 24 a, 24 b around the cores 28 a, 28 b, and theupper wrapper 300, the side wrapper 304, the winding nip roller 402, andthe lower winding roller 404 are successively retracted from the cores28 a, 28 b.

Specifically, after the elongate films 24 a, 24 b are wound around thecores 28 a, 28 b through about 180° from the position where the elongatefilms 24 a, 24 b have been held by the lower winding roller 404, thewinding rip roller 402 and the lower winding roller 404 are spaced awayfrom the cores 28 a, 28 b. After the elongate films 24 a, 24 b are woundaround the cores 28 a, 28 b further through about 90°, the side wrapper304 is spaced away from the cores 28 a, 28 b. When one turn or more ofthe elongate films 24 a, 24 b is subsequently wound around the cores 28a, 28 b (e.g., through about 540°), the upper wrapper 300 is spaced awayfrom the cores 28 a, 28 b.

Therefore, when the elongate films 24 a, 24 b are initially wound, theleading ends of the elongate films 24 a, 24 b are pressed against andsupported by the first through fourth free rollers 320 a, 320 b, 332,334 of the block wrapper 60, without sagging in the gaps 319, 331between the blocks 317, 329 and the cores 28 a, 28 b. Stated otherwise,since the elongate films 24 a, 24 b are wound around the cores 28 a, 28b with only their leading end being held in position, the elongate films24 a, 24 b are prevented from sagging under their tension, making itpossible to efficiently produce high-quality rolls 30 a, 30 b in adesired wound configuration that is reliably maintained through a simpleprocess.

The times at which the upper wrapper 300, the side wrapper 304, thewinding nip roller 402, and the lower winding roller 404 are moved areset based on the output signal from the encoder 41 that is coupled tothe suction drum 38 which serves as a reference roller. The wound stateof the elongate films 24 a, 24 b around the cores 28 a, 28 b can beaccurately detected, and the wrappers and the rollers can optimally beretracted based on the detected wound state of the elongate films 24 a,24 b, effectively avoiding winding failures of the elongate films 24 a,24 b. Consequently, the elongate films 24 a, 24 b can smoothly be woundaround the cores 28 a, 28 b in a stable wound configuration, producinghigh-quality rolls 30 a, 30 b.

While the elongate films 24 a, 24 b are being wound around the cores 28a, 28 b by the core rotating mechanism 58, the unit body 200 on whichthe block wrappers 60 are mounted is temporarily moved in a directionaway from the cores 28 a, 28 b, i.e., in the direction indicated by thearrow C1 in FIG. 7, by the ball screw 212 that is rotated by theservomotor 206 through the belt and pulley means 210. As shown in FIG.15, the pusher 550 of the core supply mechanism 68 holds new cores 28 a,28 b and moves upwardly, and places the new cores 28 a, 28 b in the coretransfer position P3.

When the new cores 28 a, 28 b are placed in the core transfer positionP3, a given number of block wrappers 60 positioned along the axiallength of the cores 28 a, 28 b are moved in unison with each other tothe core transfer position P3 by the unit body 200. Thereafter, as shownin FIG. 8, the cylinder 310 of the lifting and lowering means 302 isactuated to lower the upper wrapper 300 to support upper portions of thecores 28 a, 28 b. Then, the core supply mechanism 68 releases the cores28 a, 28 b, and the cylinder 322 of the moving means 306 is actuated tomove the side wrapper 304 forward, supporting side and lower portions ofthe cores 28 a, 28 b (see FIG. 16). The pusher 550 is lowered, therebytransferring the new cores 28 a, 28 b to the block wrappers 60.

When the elongate films 24 a, 24 b are wound to a given length aroundthe cores 28 a, 28 b by the core rotating mechanism 58, as shown in FIG.16, the nip roller 56 is moved toward the backup roller 54, suppressingtension variations in an upstream film path portion, and the productreceiving mechanism 64 is elevated. On the product receiving mechanism64, the rolls 30 a, 30 b are held by the rider roller 538, the ejectionroller 518, and the free roller 526. The servomotor 502 is energized torotate the balls crew 506, causing the block 514 to lower the rolls 30a, 30 b to a vertical cutting position. At this time, since the rolls 30a, 30 b are lowered while unwinding the elongate films 24 a, 24 b, theelongate films 24 a, 24 b are kept under tension.

Then, the drive unit 202 is actuated to move the unit body 200 forwardin the direction indicated by the arrow C2, and new cores 28 a, 28 b areheld by the core rotating mechanism 58. The unit body 406 is movedforward to cause the winding nip roller 402 to press the elongate films24 a, 24 b against the outer circumferential surfaces of the cores 28 a,28 b.

Then, as shown in FIG. 10, the rodless cylinder 430 of the cuttingmechanism 66 is actuated, moving the base member 434 in unison therewithin the transverse directions of the film, i.e., in the directionsindicated by the arrow D. Therefore, the first pinion 440 meshing withthe rack 438 extending in the directions indicated by the arrow D andthe second pinion 442 meshing with the first pinion 440 are rotated torotate and move the cross cutter blade 446 in the directions indicatedby the arrow D, cross-cutting the elongate films 24 a, 24 b transverselywhile they are being guided by the sorting guide 448.

After the elongate films 24 a, 24 b are cut, as shown in FIG. 9, thecylinder 414 is actuated to move the lower winding roller 404 in unisonwith the lower plate 410 forward in the direction indicated by the arrowC1. Therefore, as shown in FIG. 17, the cut leading end portions of theelongate films 24 a, 24 b are wound around the cores 28 a, 28 b throughabout 90°.

Then, as shown in FIG. 18, the elongate films 24 a, 24 b are woundaround the cores 28 a, 28 b. On the product receiving mechanism 64, theservomotor 520 is energized to rotate the product in the windingdirection, winding the cut trailing ends of the elongate films 24 a, 24b to a suitable length. The product is transferred from the productreceiving mechanism 64 to the conveyor 528, which supplies the productto a next process.

In the second embodiment, as shown in FIG. 8, the first and second freerollers 320 a, 320 b are pressed against the outer circumferentialsurfaces of the cores 28 a, 28 b, and the direction in which the firstand second free rollers 320 a, 320 b are pressed, i.e., the directionindicated by the arrow V2, is opposite to the direction in which theelongate films 24 a, 24 b wound around the cores 28 a. 28 b aretensioned, i.e., the direction indicated by the arrow V1.

Consequently, the first and second free rollers 320 a, 320 b are capableof applying pressing forces to the cores 28 a, 28 b whilecounterbalancing the tension that is applied to the cores 28 a, 28 bwhen the elongate films 24 a, 24 b are wound therearound, thus reliablypreventing the cores 28 a, 28 b from being flexed. Thus, the elongatefilms 24 a, 24 b are prevented from being transported unstably, and aresmoothly and reliably wound around the cores 28 a, 28 b, providing astable wound configuration.

The first and second free rollers 320 a, 320 b are positioned at equaldistances K from the hypothetical reference line LV. Therefore, thefirst and second free rollers 320 a, 320 b are stably and firmlysupported on the output circumferential surfaces of the cores 28 a, 28b, and the block 317 on which the first and second free rollers 320 a,320 b are mounted does not need to rely on its own rigidity, allowingthe gap 319 to be maintained reliably between the block 317 and thecores 28 a, 28 b.

The elongate films 24 a, 24 b can thus smoothly be wound along the gap319 and hence can be wound efficiently and highly accurately. The fourthfree roller 334 is disposed in substantially opposite relation to thefirst and second free rollers 320 a, 320 b about the cores 28 a, 28 b,thereby reliably supporting the cores 28 a, 28 b.

The third free roller 332 and the winding nip roller 402 are disposed onthe hypothetical reference line LH in opposite relation to each otherabout the cores 28 a, 28 b. Therefore, pressing forces applied by thethird free roller 332 and the winding nip roller 402 are held inequilibrium, preventing the cores 28 a, 28 b from being flexed along thehypothetical reference line LH.

A predetermined number of block wrappers 60 corresponding to the axiallength of the cores 28 a, 28 b are arrayed in the axial direction of thecores 28 a, 28 b, and apply pressing forces to the cores 28 a, 28 b overtheir entire length. Accordingly, uniform pressing forces can be appliedto the cores 28 a, 28 b in the entire axial direction, so that the cores28 a, 28 b can be maintained linearly over their entire length.Specifically, as shown in FIG. 19, if the cores 28 a, 28 b held by onlythe core chucks 90 a, 90 b are rotated by the core rotating mechanism 58to wind the elongate films 24 a, 24 b around the cores 28 a, 28 b, thecores 28 a, 28 b are liable to be largely flexed in their centralregion. However, as shown in FIG. 20, when the cores 28 a, 28 b arerotated while pressing forces are being applied to the cores 28 a, 28 bover their entire length by the block wrappers 60, the cores 28 a, 28 bcan be maintained linearly over their entire length, preventing thewound configuration of the elongate films 24 a, 24 b from beingdisturbed.

By setting dimensions of the gaps 319, 331 between the blocks 317, 329and the cores 28 a, 28 b, it is possible to wind the elongate films 24a, 24 b neatly around the cores 28 a, 28 b. Specifically, when the baseof the elongate films 24 a, 24 b was made of PET, the elongate films 24a, 24 b had a thickness of 0.1 mm, the outside diameter of the cores 28a, 28 b was in the range from 50 mm to 90 mm, and the gaps 319, 331 werein the range from 0.1 mm to 0.8 mm, i.e., in the range from thethickness of the elongate films 24 a, 24 b to 0.8 mm, a stable woundconfiguration was obtained. When the gaps 319, 331 were in the rangefrom 0.8 mm to 1.2 mm, the elongate films 24 a, 24 b tended to floatfrom the cores 28 a, 28 b. When the gaps 319, 331 were greater than 1.2mm, the wound state was unstable, and a winding failure was caused.Therefore, the gaps 319, 331 should preferably be in the range from thethickness of the elongate films 24 a, 24 b to 0.8 mm.

According to the second embodiment, furthermore, the block 317 with thefirst and second free rollers 320 a, 320 b mounted thereon is movabletoward and away from the cores 28 a, 28 b by an actuator with a pressingforce adjusting function, e.g., the vertical cylinder 310. The tensionof the elongate films 24 a, 24 b when they are wound around the cores 28a, 28 b is in the range from 9.8 N (Newton) to 29.4 N (Newton) per 100mm of the film, and is controlled by the torque produced by theservomotor 92 of the core rotating mechanism 58. The servomotor 92 maybe replaced with a combination of an induction motor and a powder brake,a combination of an induction motor and a hysteresis clutch, or acombination of a speed-controlled motor and a dancer.

The pressing forces of the upper wrapper 300 are set by a regulator tobe of the same value as the above tension value. For example, in thecase where the block wrapper 60 has a width of 100 mm, the cylinder 310has a bore diameter of 10 mm, and the upper wrapper 300 has a weight of4.9 N (Newton), if the film tension value is 19.6 N (Newton) per 100 mm,then the pressing forces of the upper wrapper 300 are 18.6×10⁴ Pa(Pascal).

The cores 28 a, 28 b are apt to have a more flexible region in the axialdirection thereof. If, for example, the pressing forces of the blockwrapper 60 disposed at the centers of the cores 28 a, 28 b are higherthan those of the other block wrappers 60, then the cores 28 a, 28 b canaccurately be corrected out of their flexed configuration.

If there is employed a mechanism capable of automatically controlling apressure in ganged relation to the set tension value of the elongatefilms 24 a, 24 b when they are wound, then transverse film sizes can bechanged automatically when the tension is changed according totransverse film size. By individually controlling the cylinders 310 ofthe respective block wrappers 60, the cores 28 a, 28 b can be pressed soas to be slightly flexed in a direction opposite to the direction inwhich it is flexed under tension. Accordingly, the stability with whichto transport the elongate films 24 a, 24 b is increased to reliablyobtain a stable wound configuration.

In the second embodiment, the winding nip roller unit 400 is employed.However, the winding nip roller unit 400 may be replaced with a windingnip roller unit 400 a shown in FIG. 21. The winding nip roller unit 400a has a cylinder 570 for moving the winding nip roller 402 in thedirections indicated by the arrow C. The cylinder 570 has a rod 572extending therefrom and coupled to a movable upper plate 408 asupporting the winding nip roller 402 thereon. The winding nip roller402 is movable in unison with the movable upper plate 408 a when thecylinder 570 is actuated.

The elongate films 24 a through 24 d have been described as a web.However, the present invention is also applicable to any of various websincluding resin sheets, paper, etc.

According to the present invention, as described above, the web isinitially wound around the core under a low tension, thereafter woundunder a tension that increases at a given rate, and then wound under atension that progressively decreases from the high tension. The web thuswound into a roll is not damaged and the roll is in a neatly wound statefree of edge undulations or irregularities on its end faces.

The length to which the web is wound around the core under a low tensionis set so as to correspond to the length of the core, so that the webcan be neatly wound around the core without the danger of the corebecoming flexed.

According to the present invention, the core is rotated while aplurality of rollers and blocks are disposed around the core, and therollers and blocks are retracted away from the core successively fromregions where the leading end of the web has passed. Accordingly, onlythe leading end of the web is kept on the outer circumferential surfaceof the core, and the web is not loosened under the tension of the web. Ahigh-quality wound product with a desired wound configuration maintainedreliably can efficiently be obtained through a simple process.

According to the present invention, furthermore, there is disposed amovable pressing roller which is pressed against the core in a directionopposite to the direction in which the tension of at least the web isapplied, to keep the tension of the web and the pressing forces appliedby the pressing roller in equilibrium. Consequently, when the web iswound around the core, the core is prevented from being flexed under thetension of the web, making it possible to reliably obtain a stable woundconfiguration with a simple arrangement.

Although certain preferred embodiments of the present invention havebeen shown and described in detail, it should be understood that variouschanges and modifications may be made therein without departing from thescope of the appended claims.

1. A method of winding a web, comprising the steps of: supporting theweb on an outer circumferential surface of a core with a plurality ofrollers, and rotating the core with a gap being defined by blocksbetween the blocks and the outer circumferential surface of the core forpassage of the web therethrough; retracting said rollers and said blocksfrom the core successively from regions where a leading end of the webhas passed; and after the web is wound around the core by at least oneturn, retracting all the said rollers and said blocks from the core. 2.A method according to claim 1, wherein a time to move said rollers andsaid blocks is determined based on an output signal from an encoderwhich is associated with a reference roller for feeding said web.
 3. Anapparatus for winding a web around a core, comprising: a core rotatingmechanism for rotating the core; and a winding mechanism for guiding theweb around the core when the core is rotated; said winding mechanismcomprising: a movable pressing roller for pressing the web against thecore to support the web thereon and for being pressed against the corein a direction opposite to the direction in which the tension of atleast the web is applied; and a plurality of movable blocks for creatinga gap for passage of the web between the movable blocks and an outercircumferential surface of the core.
 4. An apparatus according to claim3, wherein said pressing roller includes first and second pressingrollers symmetrically positioned with respect to a hypotheticalreference line which extends parallel to the direction indicated inwhich the tension of the webs is applied and also extends throughcenters of the cores, said first and second pressing rollers beingrotatably mounted on one of said blocks.
 5. An apparatus according toclaim 4, wherein said block on which said first and second pressingrollers are rotatably mounted is movable toward and away from the coreby an actuator with a pressing force adjusting function.
 6. An apparatusaccording to claim 4, wherein said winding mechanism comprises: abearing roller for engaging the core in opposite relation to said firstand second pressing rollers; and a third pressing roller and a windingnip roller which are disposed on a hypothetical line which extendsacross said hypothetical reference line and also extends through centersof the core, and which are disposed in sandwiching relation to the core,said third pressing roller and said winding nip roller being movabletoward and away from each other.
 7. An apparatus according to claim 3,wherein said winding mechanism comprises a plurality of windingmechanisms arrayed axially of the core, with only a predetermined numberof winding mechanisms, depending on the axial length of the core, amongsaid plurality of winding mechanisms being disposed in a position towind the web.